Commercial and industrial storage tanks are widely used for storing a great variety of liquids. Some of these liquids are highly corrosive and/or are flammable. The service life of a storage tank will vary, depending upon environmental conditions, including the liquid being stored. Eventually, however, the tank will become corroded and develop leaks. This can result in a significant danger to the environment and health of nearby residents. For example, storage tanks are commonly used for storing gasoline at service stations. Gasoline, of course, is highly-flammable and is capable of posing a significant health and safety hazard if not properly contained. Federal as well as local regulations govern the structure of such storage tanks.
Heightened public awareness of the danger posed by storage tanks (particularly underground gasoline storage tanks) has led to additional governmental regulations. Recent proposed regulations 2 will soon require most storage tanks to have secondary containment means and possibly a fail safe design feature to guard against accidental soil, water, and air contamination. Secondary containment means must be capable of containing leaked liquid from the storage tank. Rigid double walled tanks made from sheet metal have been suggested as one alternative. While effective for containment purposes, such tanks as presently available are costly to build and difficult to install because of their weight. The tanks are built by basically forming two rigid tanks and placing one inside the other. Tanks made from fiberglass reinforced resinous material are also extensively used. Building a double walled storage tank system with fiberglass and resin by known methods is very labor intensive and costly.
Recent concerns about tank leaks has heightened the need for an efficient and economical manner of building double walled storage tank systems. There has now been discovered a method whereby storage tanks are built with a double wall for secondary containment in an efficient, yet economical manner. Such tanks can also be equipped with means to monitor for any leakage.